Pheidole roosevelti-group

Sarnat, E. M., 2008, A taxonomic revision of the Pheidole roosevelti-group (Hymenoptera: Formicidae) in Fiji., Zootaxa 1767, pp. 1-36 : 7-11

Diagnosis of the Pheidole roosevelti-group

The species of the Pheidole roosevelti-group can be distinguished from those of other congeners by the following combination of characters.

1. Mesonotum of major and minor workers with a posteriorly projecting process.

2. Mesonotal declivity of major and minor workers concave.

3. Propodeal spines elongate and either simple or modified apically into an angulate point or bifurcation.

4. Pronotal spines or projections absent.

5. Hypostoma of major worker with a well developed median tooth, one pair of inner teeth, and one pair of outer teeth.

6. Palp formula 2:2 in major and minor workers.

7. Petiole peduncle elongate.

8. Occipital carina absent dorsally.

The recent discovery of five new species and an examination of additional material for the two previously described species requires a broadening of the original diagnosis outlined by Mann (1921) for the P. roosevelti-group . Pheidole simplispinosa sp. n., with its simple propodeal spines, truncated mesonotal process and unmargined head, is both the most aberrant of the group and the primary cause for broadening the definition. However, compared to other Pheidole of the Pacific region, P. simplispinosa is more similar in morphology to the other members of the P. roosevelti-group than to any other species examined.

Synopsis of Pheidole roosevelti-group

P. bula sp. n.

P. colaensis Mann , 1921

P. furcata sp. n.

P. pegasus sp. n.

P. roosevelti Mann , 1921

P. simplispinosa sp. n.

P. uncagena sp. n.

Key to species

The following keys diagnose the known minor workers, major workers, and queens of each species included in the Pheidole roosevelti-group with the exception of the queen caste of Pheidole uncagena sp. n, which is unknown.

Minors

1 Propodeal spines simple, evenly tapering to a single straight acuminate point without becoming bifurcate or angulate apically (Figs. 21b, 48); mesonotal process truncated into a blunt process without lamellate or distinct posterior margin (Figs. 21a, 48); head as broad as long, scapes shorter, metafemur shorter (CI 0.98-1.03, SL 0.77-0.85, FL 0.80-0.91, n = 10).................................................... P simplispinosa , sp. n.

- Propodeal spines modified apically with bifurcate or angulate tip, but never evenly tapering to a single straight acuminate point (Figs. 22b, 33, 36, 39, 42, 45, 51); mesonotal process with lamellate or acute posterior margin (Figs. 22a, 33, 36, 39, 42, 51); head longer than broad, scapes longer, metafemur longer (CI 0.87-0.96, SL 0.97-1.66, n = 51)................................................................................................................2

2 Head, in full face view, smooth and shining above level of eyes (Figs. 35, 41, 50); promesonotum, in dorsal view, smooth and shining (Figs. 37, 43, 52) .......................................................................................... 3

- Head, in full face view, rugose to rugoreticulate above level of eyes (Figs. 32, 38, 44); promesonotum, in dorsal view, transversely rugose to rugoreticulate (Figs. 34, 40, 46) .......................................................... 5

3 Head venter, in profile, with genal carinae modified into elevated flanges (Figs. 25, 51); mesonotal process, in dorsal view, strongly attenuated (Figs. 24, 52); head, in full face view, oval shaped without posterolateral corners forming obtuse angles (Fig. 50); propodeal spines with dorsal edge approximately as long as anterior edge (PSI 0.87-1.13, n = 8); color of petiole, postpetiole and gaster distinctly lighter than mesosoma and head....................................................................................................... P. uncagena , sp. n.

- Head venter, in profile, with genal carinae either indistinct (Fig. 26b) or forming a collar around foramen (Fig. 27b), but never modified into elevated flanges; mesonotal process, in dorsal view, broad (Figs. 23, 37, 43); head, in full face view, subquadrate with posterolateral corners forming obtuse angles (Figs. 35, 41); propodeal spines with dorsal edge either distinctly shorter than anterior edge (PSI 0.29-0.77, n = 8) or distinctly longer than anterior edge (PSI 1.46-1.71, n = 9); color of petiole, postpetiole and gaster either lighter or same as mesosoma and head........................................................................................................ 4

4 Propodeal spines with dorsal edge distinctly longer than anterior edge (PSI 1.46-1.71, n = 9) (Figs. 13, 42); posterior of head strongly pinched dorsoventrally (Figs. 27a, 42), appearing flattened in profile and shield-like in full face view; color of petiole, postpetiole and gaster distinctly lighter than mesosoma and head; scapes longer, metafemur longer (SL 1.21-1.27, FL 1.58-1.66, n = 9)................. P. pegasus , sp. n.

- Propodeal spines with dorsal edge distinctly shorter than anterior edge (PSI 0.29-0.77, n = 8) (Figs. 14, 36); posterior of head weakly pinched dorsoventrally (Figs. 26a, 36), but not appearing flattened in profile or a shield-like in full face view; color of petiole, postpetiole and gaster same as mesosoma and head; scapes shorter, metafemur shorter (SL 0.99-1.06, FL 1.12-1.23, n = 8).................................. P. colaensis

5 Head venter smooth and shining (Fig. 39); in profile, genal carinae inconspicuous (Figs. 26b, 39)............ ........................................................................................................................................... P. furcata , sp. n.

- Head venter sculptured (Figs. 33, 45); strongly produced genal carinae present (Figs. 28b, 33, 45).........6

6 Head, in full face view, with strongly branching network of longitudinal and transverse rugae (Fig. 44); spaces between head rugoreticulum strongly foveolate; pronotum, in dorsal view, rugoreticulate (Fig. 46); mesonotal process, in dorsal view, broadly lamellate and with a medially excised posterior margin (Fig. 46)............................................................................................................................................. P. roosevelti

- Head, in full face view, with discontinuous longitudinal rugae that branch occasionally, but become rugoreticulate only on posterolateral corners of head (Fig. 32); spaces between head rugae smooth and shining; pronotum, in dorsal view, shining with transverse rugae (Fig. 34); mesonotal process, in dorsal view, narrowly lamellate with flat to weakly concave posterior margin (Fig. 34)........................... P bula , sp. n.

Majors

1 Mesonotal process, in profile, truncated into a blunt angle without lamellate or acute posterior margin (Figs. 8a, 69); propodeal spines simple, evenly tapering to a single straight acuminate point without becoming bifurcate or angulate apically (Figs. 8b, 69); posterolateral lobes, in full face view, with distinct transverse rugae extending from median cleft to posterolateral corners (Figs. 11, 68); scapes short (SL 0.73-0.84, n = 9)...................................................................................................... P. simplispinosa , sp. n.

- Mesonotal process, in profile, with acute posterior angle or lamella (Figs. 9a, 10a, 54, 57, 60, 63, 66, 72); propodeal spines usually modified apically with bifurcate or angulate tip (Figs. 9b, 10b, 54, 57, 60, 63, 66, 72); posterolateral lobes, in full face view, variably sculptured but never with distinct transverse rugae extending from median cleft to posterolateral corners (Figs. 53, 56, 59, 62, 65, 71); scapes of variable length (SL 0.90-1.19, n = 35).....................................................................................................................2

2 Posterolateral lobes, in full face view, smooth and shining without rugae or carinae (Figs. 12a, 56); median ocellus present and well developed (Figs. 12b, 56); intercarinular spaces on head smooth and shining; postpetiole with anterior face and dorsum smooth and shining without rugulae; gaster with basal portion of first tergite smooth and shining (Fig. 58) ................................................................. P. colaensis

- Posterolateral lobes, in full face view, sculptured with rugae or carina (Figs. 53, 59, 62, 65, 68, 71); median ocellus present or absent; intercarinular spaces on head smooth and shining to foveolate; postpetiole with anterior face and dorsum smooth and shining to rugulose-foveolate; gaster with basal portion of first tergite smooth and shining to densely sculptured ................................................................................ 3

3 Posterolateral lobes, in full face view, rugoreticulate, such that longitudinal rugae are intersected by transverse rugae (Figs. 53, 59, 65); pronotum, in dorsal view, rugoreticulate, such that transverse rugae are often intersected by longitudinal rugae (Figs. 55, 61, 67); sides of petiole, in posterior view, subparallel without laterally projecting processes ......................................................................................................... 4

- Posterolateral lobes, in full face view, carinate, such that longitudinal carinae are not intersected by transverse carinae (Figs. 62, 71); pronotum, in dorsal view, rugose, such that transverse rugae not intersected by longitudinal rugae (Figs. 64, 73); sides of petiole, in posterior view, emarginated with laterally projecting processes................................................................................................................................................ 6

4 Posterolateral lobes, in full face view, with rugoreticulum terminating before obtaining posterior margin (Fig. 59); in dorsal view, length of median basigastral sculpturing immediately posterior to postpetiole attachment longer than length of postpetiole (Figs. 15, 61); head shorter (HL 1.95-2.04, n = 7)................ ........................................................................................................................................... P. furcata , sp. n.

- Posterolateral lobes, in full face view, with rugoreticulum obtaining posterior margin (Figs. 53, 65); in dorsal view, length of median basigastral sculpturing immediately posterior to postpetiole attachment shorter than length of postpetiole (Figs. 55, 67); head longer (HL 2.06-2.38, n = 13)...............................5

5 Head, in full face view, with intercarinular spaces densely and distinctly foveolate (Fig. 65); postpetiolar dorsum, in dorsal view, rugulose with foveolate interspaces; scapes shorter relative to head (SI 0.41-0.46, n =8)......................................................................................................................................... P. roosevelti

- Head, in full face view, with intercarinular spaces smooth and shining to weakly impressed, but never densely nor distinctly foveolate (Fig. 53); postpetiolar dorsum, in dorsal view, smooth and shining; scapes longer relative to head (SI 0.48-0.53, n = 5).......................................................................... P. bula , sp. n.

6 Propodeal spines, in profile, with dorsal edge as long as or longer than anterior edge (Figs. 17, 63); mesonotal process, in dorsal view, broad basally (Figs. 19, 64); petiole with posterior face smooth and shining; head wider, metafemur longer, scapes longer (HW 2.20-2.35, FL 1.59-1.66, SL 1.15-1.19, n = 3) P. pegasus , sp. n.

- Propodeal spines, in profile, with dorsal edge distinctly shorter than anterior edge (Figs. 18, 72); mesonotal process, in dorsal view, strongly attenuated basally (Fig. 20, 73); petiole with posterior face rugoreticulate; head narrower, metafemur shorter, scapes shorter (HW 2.05-2.12, FL 1.51-1.57, SL 1.09-1.12, n = 5).................................................................................................................................... P. uncagena , sp. n.

Queens

1 Propodeal spines simple and straight, evenly tapering to a single acuminate point without becoming bifurcate or angulate apically (Figs. 29, 90); scapes short (SL 0.87, FL n = 1).............. P simplispinosa , sp. n.

- Propodeal spines modified apically with bifurcate or angulate tip, but never evenly tapering to a single straight acuminate point (Figs. 30, 31, 75, 78. 81. 84. 87); scapes long (SL 0.97-1.24, n = 15)...............2

2 Mesonotum, in profile, lower than pronotum (Figs. 31, 75, 78, 81); pronotum, in dorsal view, largely visible(Figs. 76, 79, 82); sides of head, in full face view, subparallel or weakly diverging posteriorly (Figs. 74, 77, 80); head narrow (HW 1.12-1.35, n = 8)........................................................................................3

- Mesonotum, in profile, subequal in height to pronotum (Figs. 30, 84, 87), pronotum, in profile, largely concealed by mesonotum (Figs. 85, 88); sides of head, in full face view, strongly diverging posteriorly (Figs. 83, 86); head broad (HW 1.55-1.95, n = 7)......................................................................................5

3 Head venter densely sculptured; anterior face of postpetiole with regular longitudinal rugulae.................. ................................................................................................................................................ P. bula , sp. n.

- Head venter smooth and shining; postpetiole with anterior face either smooth and shining or with weak irregular sculpture, but never with regular longitudinal rugulae ................................................................. 4

4 Head with posterolateral corners smooth and shining (Fig. 77); petiolar node, in posterior view, concave; postpetiolar dorsum smooth and shining; in dorsal view, length of median sculpturing immediately posterior to postpetiole attachment shorter than length of postpetiole (Fig. 16); head wider and longer (HW 1.29-1.35, HL 1.27-1.30, n = 3)............................................................................................... P. colaensis

- Head with posterolateral corners rugoreticulate and with intercarinular spaces foveolate (Figs. 80); petiolar node, in posterior view, flat; postpetiolar dorsum transversely striate; in dorsal view, length of median sculpturing immediately posterior to postpetiole attachment equal to or longer than length of postpetiole (Fig. 15); head narrower and shorter (HW 1.12-1.18, HL 1.14-1.17, n = 3)................... P. furcata , sp. n.

5 Head, in full face view, with posterior portion rugoreticulate such that irregular longitudinal rugae are often intersected by irregular transverse rugae (Fig. 86); ground sculpture between eyes and frontal carinae densely and distinctly foveolate; head narrower and shorter (HW 1.55-1.70, HL 1.37-1.52, n = 6).... .................................................................................................................................................. P. roosevelti

- Head, in full face view, with posterior portion longitudinally carinate such that longitudinal carinae may occasionally branch, but are never intersected by transverse carinae or rugae (Fig. 83); ground sculpture between eyes and frontal carinae smooth and shining; head wider and longer (HW 1.96, HL 1.73, n = 1).... ......................................................................................................................................... P. pegasus , sp. n.